A conveyor system generally includes a flexible belt (often made of rubber) that loops about two rollers: a front drive roller that powers the conveyor system, and a tail roller. As the rollers rotate, the conveyor can carry (“convey”) an object placed on the belt. Over time, the flexible belt tends to stretch and deform, resulting in the belt slipping over the rollers and the conveyor system being unable to effectively move the belt. To avoid such slippage, the tail roller is often provided with an extendable and retractable belt tightener that applies tension to the belt so that there is enough friction for the drive pulley to move the belt. The belt tightener is often used to apply tension during the life of the conveyor system. Belt tighteners for conveyor and other endless belts are exemplified by the devices depicted in (for example): U.S. Pat. No. 3,832,910 to Bryant; U.S. Pat. No. 4,803,804 to Bryant; U.S. Pat. No. 5,030,173 to Bryant; U.S. Pat. No. 5,054,608 to Bryant; and U.S. Pat. No. 5,259,821 to Bryant (the entireties of these patents being incorporated herein by reference).
As shown in FIGS. 1A and 1B, a conventional belt tightener 1 includes a “take-up” having an elongated inner sleeve/tube 5 of lesser diameter that extends from and retracts into a “body” 10 (an elongated outer sleeve/tube) of larger diameter. Conventional belt tighteners also include a pillow block 15 that is secured to the take-up 5 via a bearing plate/mounting plate 20. The pillow block 15 receives a bearing 25 through which a roller shaft may pass.
The design of tightener 1 has been in use for many years, and it suffers from several noteworthy disadvantages. Mounting pillow blocks to standard bearing plates requires nuts and bolts. Such nuts and bolts are collection points for contamination and bacteria, which is undesirable especially in food-grade applications. Also, imperfect installation of the pillow block will place parts out of alignment (even if only slightly), subjecting the components to shear forces, increasing wear-and-tear, and wasting energy.
These and other failures are addressed by the exemplary improved belt tighteners discussed below and depicted in the attached figures.